CME Group's move to acquire Dow Jones' stock market Indexes arm was approved yesterday by the US Department of Justice and the Federal Trade Commission, as many incumbent exchanges are starting to diversify their businesses amid falling market shares.

CME, the Chicago-based derivatives exchange, announced last month that it intended to purchase a 90% stake in Dow Jones Indexes, the stock market indices business which includes The Dow Jones Industrial average, one of the best-known market benchmarks.